1. Field of the Invention
The present invention relates to a high voltage electrode for an electric double layer capacitor and a method of manufacturing the same and, more particularly, to a high voltage electrode for an electric double layer capacitor and a method of manufacturing the same, which are capable of implementing a high voltage electrode by preventing a loss of the surface area of an aluminum sheet that is used in an electrode for an electric double layer capacitor so that a contact area between the aluminum sheet and an active material sheet is increased when forming a plurality of through holes in the aluminum sheet and by forming a metal oxidation layer on the entire surface of the aluminum sheet.
2. Description of the Related Art
An electric double layer capacitor (EDLC) has a less influence on the lifespan although it is repeatedly charged and discharged because it stores electric energy using a physical adsorption phenomenon with reversibility and is being applied to smart phones, hybrid vehicles, electric vehicles, and the energy storage device field applied to solar cell generation. The electric double layer capacitor has an excellent power density, but has a low energy density. Accordingly, there is a need to develop materials for electrodes in order to improve the low energy density problem.
Korean Patent No. 1166148 (Patent Document 1) relates to a method of manufacturing an aluminum current collector having a three-dimensional pattern structure using photolithography. In the method of manufacturing the aluminum current collector disclosed in Patent Document 1, first, after an aluminum foil current collector is washed, it is dried using nitrogen atmosphere. Thereafter, a photoresist solution is coated on a surface of the dried aluminum foil current collector and then dried and cured so that the photoresist solution is selectively exposed.
Thereafter, the photoresist solution that has not been exposed is selectively removed by scattering a developer on the aluminum current collector that has been exposed so that the remaining photoresist solution is fully cured, thereby forming a pattern on the aluminum current collector. The aluminum foil current collector in which the pattern has been formed is placed between two carbon plates, that is, opposite electrodes, AC power is applied to the aluminum foil current collector, and primary etching is performed on the aluminum current collector in an electrolyte.
Thereafter, the etched aluminum current collector is dried. Next, the aluminum current collector dried after the primary etching is placed between the two carbon plates, that is, opposite electrodes, and secondary etching is performed on the aluminum current collector. Thereafter, the aluminum foil subjected to the secondary etching is washed and dried.
As in Patent Document 1, the energy density of a conventional electrode for an electric double layer capacitor is improved by forming a pattern, that is, a plurality of through holes, in an aluminum current collector using a photolithography process so that a contact area between the aluminum current collector and active materials is increased.
If a plurality of through holes is formed in an aluminum current collector that is used in a conventional electrode for an electric double layer capacitor as in Patent Document 1, however, there is a problem in that the surface area of the aluminum current collector is lost by an area that belongs to a total area of the aluminum current collector and that is occupied by the through holes.